Improper access control in Unbound - CVE-2026-55708
Published: July 23, 2026
Vulnerability identifier: #VU139224
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-55708
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: NLnet Labs
Affected software:
Unbound
Unbound
Detailed vulnerability description
The vulnerability allows a remote user to bypass local DNS policy protections.
The vulnerability exists due to improper access control in the unbound-control view_local_data and view_local_datas command handling when creating local zones for an already configured named view with no local data. A remote user can invoke the control interface to bypass local DNS policy protections.
Queries for default-protected names from clients mapped to the affected view may be forwarded to the public DNS instead of being answered locally.
How to mitigate CVE-2026-55708
Install security update from vendor's website.